REANA-Client 0.6.0

• Introduces user secrets management commands secrets-add,
  secrets-list and secrets-delete.
• Enhances run and create commands to allow specifying
  workfow via the --workflow flag.
• Introduces new command version to report client version.
• Fixes upload command behaviour for uploading very large files.
• Simplifies run command by removing free upload parameters.
• Upgrades cwltool to 1.0.20191022103248.
• Disables SSL verification warnings when talking to self-signed server
  certificates.